# Tesla coil primary driver using the ordinary inverter.

#### Martin Arpon

Joined Jul 20, 2019
5
But can I change the operating frequency of the second stage of inverter from 50 hz to whatever is the maximum operating frequency of the IC that drives the second stage of the inverter, am I right? Coz we know the ordinary inverter today has two stage, 1st is to boost the 12V to 330V by using ferrite transformer that operates at high frequency and 2nd is to feed the 330V to full bridge inverter that operates at 50hz, that's my plan to change the operating frequency of the second stage.

#### TeeKay6

Joined Apr 20, 2019
572
But can I change the operating frequency of the second stage of inverter from 50 hz to whatever is the maximum operating frequency of the IC that drives the second stage of the inverter, am I right? Coz we know the ordinary inverter today has two stage, 1st is to boost the 12V to 330V by using ferrite transformer that operates at high frequency and 2nd is to feed the 330V to full bridge inverter that operates at 50hz, that's my plan to change the operating frequency of the second stage.
"...that's my plan to change the operating frequency of the second stage." You may well discover that that is far more easily said than done. Because a circuit operates well at 50Hz is scarcely a guarantee of good operation at 10Khz. If you can provide the schematic for the inverter, it would be easier to reply with more detail.

#### MisterBill2

Joined Jan 23, 2018
8,446
This certainly appears to be the middle of a conversation with nothing to be seen by those who have not seen the start. Very confusing, as a result.

#### MisterBill2

Joined Jan 23, 2018
8,446
OK, now I see the context of the conversation. The plan would be to utilize the sections of some UPS that has a first stage that is an inverter with a DC output of 330 volts DC without modification, and then to utilize some portion of the section that uses the 330 volts DC to drive a transformer that delivers 120 volts 50hz to instead deliver a much higher frequency to the primary of a Tesla coil.
That is an interesting concept indeed.
All of the UPS systems that I have investigated use semiconductor devices that may not perform quite as well at a frequency approaching one megahertz. The challenge that would be the biggest barrier would be that all of the frequency control is done in a custom integrated circuit and is not subject to modification. In addition, it may well be that the UPS selected actually runs as a switchmode power supply, building the output waveform using a PWM (pulse width modulation) arrangement to build a 50 HZ waveform. I think that a very modern UPS may do that to avoid needing a heavy transformer. If that is the case I predict that the complexity will be very great.
BUT it should be very possible to use that 330 volts DC to power an oscillator circuit feeding the Tesla coil primary in a far more traditional approach. An important thing to keep in mind is that the Tesla coil must operate at it's resonant frequency rather than at some selected one.